Nondestructive testing (NDT) to identify defects in various electrical components of overhead electrical power line systems is known. NDT is often considered a preferred testing method as NDT allows for testing without destroying an object so that material qualities of an object can be examined, tested and studied without taking the object apart. NDT may be undertaken at various stages in the life cycle of an electrical component, for example, NDT may be undertaken during manufacture of the electrical component or during construction of an electrical power system to ensure that the electrical component is assembled correctly during said construction or during maintenance of the electrical power system to detect deterioration in the electrical component produced by the operating conditions or any combination of these stages. The defects detected by NDT may include but are not limited to structural flaws such as cracks, dents or pits in the electrical component, installation flaws including incorrect contact between the electrical component and a cooperating component or structure or development of leakage path(s) on the electrical component or between the electrical component and a cooperating component or structure. Ensuring the integrity of electrical power line systems, specifically where, the electrical power systems are conducting high or transmission class voltages in the range of 69 kV to over 500 kV is particularly important. NDT has proven to be a useful method for quality control in electrical power applications, in which component failure could have catastrophic results.
The terms “electrical component” or “electrical power line component” as used herein is understood to include electrical power line cables or wire products including electrical conductors, static lines, optical ground wires (OPGWs) or substation bus pipes and couplings or couplers associated with said cables. The terms “electrical component” or “electrical power line components” also include piece parts and devices including electrical components incorporating an insulating material such as an outdoor insulator. For ease of reference, electrical conductors, static lines, optical ground wires (OPGWs) or substation bus pipes are interchangeably referred to herein as “power line cabling” or “power line cable” or “power line conductor”. Couplings may include but are not limited to compression sleeves which join ends of two power line cables together or dead-ends or dead end connectors which are used to attach power line cables to supporting structures such as support towers or poles.
U.S. Pat. No. 9,488,603 to Stock discloses a portable system for non-destructive testing of overhead electrical power-line equipment (herein referred to as the Stock system). The system includes an X-ray system and a support unit. All the components of the X-ray system are mounted to a base of the support unit. The support unit further includes a plurality of attachment members. In use, the plurality of attachment members suspends the support unit from an overhead power line so as to locate the base and at least a portion of the X-ray system below the object such as power line or coupler to be imaged. The X-ray system includes an X-ray source which is mounted to the base. The X-ray source provides X-rays which penetrate the object to be imaged. The X-rays passing through the object are captured by a digital imager which, in the use position, is positioned substantially on an opposing side of the object (as compared to the X-ray source). The digital imager processes the captured X-rays and creates a digital image which is representative of the state of the object and any defects that may exist therein. Wireless communication with a remote computer to transmit the digital images is also disclosed.
Applicant believes that the Stock system cannot be safely used without modification when the power line is energized.
Further, Applicant believes that the Stock system may not be conducive for testing components in a crowded environment such as an electric substation where anchoring of the Stock system on the object to be imaged may not be possible or may be difficult. An electric substation is a junction where usually more than two power line cables terminate. In large electric substations the total number of power line cables terminating exceeds one or two dozen. The terminating power line cables connect to bus conductors or bus pipes in the electric substation. Electric substations are typically crowded as they contain a multitude of components such as support structures for the terminating power line cables and bus pipes, switches, capacitor banks and/or transformers.
Applicant believes that use of the Stock system to test components such as power line cables or bus pipes in an electric substation or overhead power line systems presents the following problems; firstly, in order to use the Stock system, the overhead power line systems or substation must be shut down in order to de-energize the power line conductors or bus pipes. This is not efficient as shutdown would result in a power outage.
The Stock system requires suspension of the NDT equipment from the object to be imaged, for example from a power line conductor or bus pipe. In an electric substation or overhead power line system, due to the often tight spacing between various electrical components and because the Stock system has a large physical footprint, it may be difficult to maneuver the Stock system so as to suspend it from the object to be imaged without risk of snagging onto surrounding electrical components and thereby causing electrical incidents.
Applicant further believes that the Stock system may not prove useful in instances where orientation of an electrical component or a lack of strength of the electrical component does not safely allow for suspension of the Stock system's equipment from the electrical component to be imaged. For example, in order to suspend the Stock system, the electrical component to be imaged must be substantially horizontal. Also, the electrical component must be sufficiently strong to support the weight of the Stock system (approximately 30 to 35 lbs.) as the Stock system requires suspension from the electrical component.
Therefore, there is a need for an apparatus and corresponding method employing the apparatus, which can test electrical components in a sub-station or elsewhere while the components are in an energized state, irrespective of their location or orientation in an overhead electrical power line system.